Construction of roll for machinery and the manufacture thereof



June 3, 1969 w. E. GREENE 3,447,600

CONSTRUCTION OF L F MACHINERY AND ROL THE MANUFACTUR HEREOF Filed Sept. 25, 1966 Sheet 0f 2 ROUGH SURFACE PRIOR ART FIG. I

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ATTORNEYS June 3, 1969 w E. GREENE 3,447,600

CONSTRUCTION O F ROLL FOR MACHINERY AND THE MANUFACTURE THEREOF Filed Sept. 25, 1966 Y Sheet 2 of 2 ATTORNEYS United States Patent 3,447,600 CONSTRUCTION OF ROLL FOR MACHINERY AND THE MANUFACTURE THEREOF William E. Greene, Bronxville, N.Y., assiguor to SW Industries, Inc., Newton, Mass., a corporation of Massachusetts Filed Sept. 23, 1966, Ser. No. 581,538 Int. Cl. F28d 21/00; B21b 27/00 U.S. Cl. 165-90 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a novel roll construction of the type useful in a variety of machines, particularly paper making and processing machines, etc. The present invention relates more particularly to a roll construction of the type having a metallic core, the extremities of which are journaled, and an elastomeric cover or veneer, the physical and mechanical properties of which are particularly selected. The roll construction of the present invention, for example, is adapted for use in the press, size and breaker-stack positions of a paper making machine of the type incorporating flow means for making available a slurry of fibers in water, slice means for distributing the slurry throughout an area in a thin layer, suction means for removing the water from the slurry in the layer and roll means for advancing, squeegeeing and conditioning the layer to form paper. The present invention, from a broad standpoint, is intended for a variety of applications involving high speed and high pressure.

The primary object of the present invention is to provide a novel roll construction having a specially designed elastomeric, inner cover that is perforated by generally longitudinal channels or conduits in order to counteract the inability of its elastomeric mass to compress and in order to provide temperature control for its elastomeric mass when in operation. The elastomeric cover has an inner working region or relatively low modulus of elasticity and an outer non-Working region of relatively high modulus of elasticity, the inner working region providing the channels and the outer non-working region providing a durable surface. In a conventional roll, of the type presently in use, the elastomer, for example, either natural or synthetic rubber, is as a practical matter incompressible. When under pressure at the nip between a pair of rolls, the elastomer is squeezed laterally away from the nip. In other words, any increment of an elastomeric veneer that is squeezed, between its own core and the surface of another roll, in accordance with its visco-elastic properties, is displaced on both sides of the nip rather than compressed within the nip. This inability of the elastomeric mass to compress interferes with desired conditions at the nip and, therefore, with the desired function of the Patented June 3, 1969 roll cover. As the rolls turn, the complex movement and counter-movement of the elastomeric mass in the nip area results in large hysteresis heat generation. The present in vention serves in a practical manner to limit both unde sired displacement and undesired heat generation at the nip and to permit the utilization of harder outer surfaces having greater wear resistance.

Other objects of the present invention will in part be obvious and will in part appear hereinafter.

For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed disclosure, taken in connection with the accompanying drawings, wherein:

FIG. 1 illustrates the displacement of elastomeric material at both sides of the nip between a pair of rolls of ordinary construction;

FIG. 2 illustrates the compression at the nip of one of a pair of rolls constructed in accordance with the present invention;

FIG. 3 is a perspective view, partly broken away, of a roll system embodying the present invention;

FIG. 4 is an exaggerated cross-sectional view of one of the rolls of FIG. 3; and

FIG. 5 is a flow diagram of a process for fabricating rolls embodying the present invention.

As shown in FIG. 1, the ordinary roll construction is such that the elastomeric roll covering 11 when compressed between a pair of metal roll cores 13, 15, is displaced on both sides 17, 10 of the nip 21. Generally, a roll construction embodying the present invention, as shown in FIG. 2, comprises as components: a cylindrical metallic core 10, preferably composed of cast iron, bronze or steel; and a tubular cover 12, preferably composed of an elastomer, such as natural or synthetic rubber. Extending longitudinally or helically throughout the length of the roll are a series of spaced conduits 14. As shown, cover 12 includes a wear resistant outer layer 23 and a pair of inner layers 25, 27 to be described in detail below, that provide conduits 14. Circulating through conduits 14, in order to conduct away hysteresis heat is a cooling medium, for example, a liquid such as water or a gas such as air. When compressed between core 10 and another roll 15, displacement of the type shown in FIG. 1 is avoided.

As shown in FIG. 3, an inlet reservoir is provided at one end 16 of the roll and an outlet reservoir is provided at the other end 18 of the roll. Thus a continuous flow of liquid or gas may be directed through inlet reservoir 16, through various conduits '14 and through outlet reservoir 18 continuously via a supply and pump 20. As shown in FIG. 4, the cooling medium is introduced through the roll axle in the following manner. The roll core, shown at 22, is keyed to a shaft 24, which extends therethrough and is journalled at its opposite extremities. Covering the extremities of the roll are a pair of dishes, one shown at 26. Since, the structures at ends 16 and 18 are the same, only the structure at end 16 need be described. An axial bore 29 and a cross bore 28 in shaft 24 connect through a communicating bore 30 to a reservoir 32 that is defined by dish 26. The extremities of conduits 14 open into reservoir 32.

As shown in FIG. 3, preferably conduits 14 are disposed in directions which are helical with respect to the axis of rotation of the roll. When viewed from the end of the roll into which the coolant is introduced, the helical direction of the conduits is opposite that of the rotational to inch.

5 to 250 pounds per sq. inch. 0 to 20 plastometer.

A to inch.

Diameter of aperture 14 Pressure of water Hardness of outer layer Thickness of outer layer Hardness of two inner layers Less than that of outer layer. Total thickness of two inner layers /2 to one inch. Spacing between apertures /2 to one inch.

Generally the size of the aperture must be large enough so that pressure losses due to skin friction do not exceed the pressure on the conduit as it passes under the nip.

The plastometer hardness designation is well known in the art, as defined in A.S.T.M. designation D-531-56.

EXAMPLE A preferred method of coating a steel core with an apertured elastomeric coating in accordance with the present invention is as follows, as shown, in FIG. 5. After roughtening the surface of the steel core and coating it with a metal to plastic bonding medium, an inner coat of elastomer is applied. After partial curing, longitudinal or helical grooves of semi-circular or like cross-section are ground into the surface of this inner coat. Next a medial coat of elastomer is applied, air being forced into the openings defined by the grooves in such a way as to prevent the medial coat from contacting the inner surfaces of the grooves. Then an outer coat of elastomer is applied. And fiinally, the entire assemblage is cured. All of the foregoing steps are effected with compositions and under conditions that are Well known to persons skilled in the art.

In operation, water from supply and pump '20 is flowed in sequence through inlet 16, through apertures 14, through outlet 18 and back to supply and pump 20. The water pressure and the speed of the roll are established in such a way as to ensure that heat generated in the veneer is carried away by the Water, the entire process being aided by pressure in the nip in consequence of the skew relation between the conduits and the axis of the roll.

The foregoing disclosure places emphasis on two concepts. First, the utilization of the conduits to accommodate the elastomer displaced in the nip and, second, the utilization of the conduits to conduct a cooling medium. These concepts can be utilized separately. The first concept alone improves roll performance and the second concept alone enables adjusting the size of the conduits and the pressure on them so as to allow the creation nip waves as shown in FIG. 1 while gaining the benefit of cooling. Although a pump is shown in FIG. 3, in certain systems, without a pump, the roll conduits can be left open and fluid circulation is effected simply by flexing the conduits. Since certain changes may be made in the foregoing dis- .4 closure without departing from the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing be interpreted in an illustrative and not in a limiting sense.

What is claimed is:

1. A roll comprising a metallic core and an elastomeric veneer, saidveneer having an inner region adjacent to said core and an outer region spaced from said core, said inner region having a series of conduits therethrough extending from one extremity of said roll to the opposite extermity thereof along a series of spiral lines, the overall hardness of said inner region of said veneer in the vicinity of said conduits being less than the overall hardness of said outer region of said veneer at the surface thereof, the diameter of each of said conduits ranging from /8 to inch, the hardness of said outer region ranging from 0 to 20 plastometer, the thickness of said outer region ranging from ,5 to /8 inch, so that when cover is under pressure and a nip is formed the rubber under compression may be displaced into the holes and reduces substantially the build up of the elastomeric material before and after the nip.

2. A roll comprising a metallic core and an elastomeric veneer, said veneer having an inner region adjacent to said core and an outer region spaced from said core, said inner region having a series of conduits therethrough extending from one extremity of said roll to the opposite extremity thereof along a series of spiral lines, the overall hardness of said inner region of said veneer in the vicinity of said conduits being less than the overall hardness of said outer region of said veneer at the surface thereof, an inlet reservoir at one end of said roll communicating with the ends of said conduits at said one of said roll, and an outlet reservoir at the other end of said roll communicating with the ends of said conduits at said other end of said roll, so that a fluid cooling medium may be circulated through the mass of elastomeric veneer and thereby remove heat of hysteresis built up therein during operation, the diameter of each of said conduit ranging from /s to 4 inch, the hardness of said outer region ranging from 0 to 20 plastometer, the thickness of said outer region ranging from A to inch, the spacing between said conduits ranging from /2 to one inch, the pressure of said fluid cooling medium ranging from 5 to 250 pounds per square inch, the operation of the outer surface of said roll being isolated from the operation of said conduits.

References Cited UNITED STATES PATENTS 1,232,053 7/1917 Lawrence 29-113 2,374,194 4/ 1945 Grupe. 2,647,301 8/1953 Scheele 29--130 X 3,082,683 3/1963 Justus 1O093 3,349,693 10/1967 Mitchell 29130 X BILLY I. WILHITE, Primary Examiner.

US. (:1. X.R. 

